Treatment of fiber products



Patented 0a 4, 1932 arise s'rarss PATIENT OFFICE I TREADWAY B. KUNROE AND ELDER! C. LATHBOP, OF CHICAGO, ILLDfiOIS, ASSIGNOBS E0 THE CELOTEX COMPANY, OF CHICAGO, ACOBPOBATION OF DELAWARE TBEATIEN'I OF FIBRE PRODUCTS Io Drawing.

In the past, various fibrous materials, for

example the various paper making fibers,

which as av single treatment provides integrally all the desired properties of products produced from fibers.

Some of the proposed sizing treatments have been detrimental to the treatments designed to produce fungi and insect proofing and some fungi and insect proofing treatments have been detrimental to sizing treatments, and in fact so far as can be determined the problem of providing a satisfactory fiber treatment affording the several properties of water proofing, fungicidal protection and toxicity to insects has seemed utterly impossible of solution.-

In its broadest application this invention comprehends the use of a water solution of arsenic, in any form, in which while having the pulped material in suspension therein,

a'precipitating agent is added to precipitate ,a relatively insoluble simple or complex arsenical.

' It is a particular object of this invention to provide a treatment of fiber whereby there is provided an integral water proofing which at the time. rovides the desired resistance to fungi-an toxicity to insects which treatment may comprise a single step of application or which may be accomplished by a plurality of succeeding steps of treatment.

.The invention from the aspect just stated involves primarily the introduction of arsenic into a mass of fibers wherein the arsenic is caused to adhere to the fibers thereof by the addition of iron salts, primarily ferric chloride or ferrous sulphate, and which with the further inclusion of a size, as rosin, resin, parafin wax, bituminous material or the like, afibrds sizing'of the fiber. 1

the desired waterproofing or Application illed December 27, 1830. Serial No; 505,203.

An additional object of the invention is to provide a treatment as above described which will afford a means of maintaining a uniform.

color of the products produced from the fiber which has been treated therewith.

Particularly in the manufacture of insuprovides a treatment whereby a uniform color may be maintained in the finished product.

Other and further objects of the invention are to provide a fiber treatment as above described which is applied integrally -to the fiber prior to its formation into the finished product, whereby it may be uniformly and thoroughly distributed throughout the final product, and in addition, to provide a treatment which is relatively cheap, is applied at small cost, is easily applied, and wherein the losses of the various chemicals used may be maintained at a minimum. Still other and further objects of the invention will be apparent on reading the following detailed specifications of the invention, wherein there is particularly set forth a preferred treatment.

Paper, fiber boards, and the like, are made from more or less finely divided fibrous materials, principally from cotton, various woods, and other vegetative growth, such as corn stalks, sugar cane bagasse, straws, and the like. In general the raw material is prepared for use in the manufacture of the various finished roducts by means of some form of digestion and mechanical refining which serves to more or less soften the raw materials and subdivide them into their fiber elements or into relatively small fiber' bundles.

The digested and refined fibrous material latin boards, due to the fact that they are is formed into paper and board products and the like by some form of felting from a diluted water suspension wherein ordinarily the fiber content of the suspension is, at the time of felting, in the neighborhood of and which is seldom if ever above 5% in any part of the system preceding the felting operation.

The treatment of the fiber material according to this invention takes place" at any desired point between that of the subdivision of the fibrous material into its fibers, or into small fiber bundles, and is preferably applied to the fiber while in the condition ordinarily referred to as half stock, at which time the tion of ferric chloride and arsenious acid to a fiber suspension to which there has been previously added a sizing emulsion, will cause coagulation or precipitation of the substance thereof on the fiber in addition to the adsorption as previously described.

Whereas the action just described covered only ferric chloride, it is to be noted that other iron salts or combinations thereof may be substituted. An example of an alternative iron salt is ferrous chloride, or in fact the initial materials may comprise any iron salt or salts which as used are hydrolyzed to the form of a hydrated oxide of iron.

In applying this process to render fibrous materials toxic and water resistant, about 2% arsenic is added, conveniently as arsenious acid dissolvedin caustic soda or sodium carbonate, but it is to be understood that the invention does not necessarily comprehend the addition of arsenious acid only as such.

- Many ordinary forms of arsenic, as for example, sodium arsenite when in water solution, hydrolyze to form ortho-arsenious acid H AsO therefore throughout the specification the term arsenious acid is used to designate a Water solution of arsenic in which the arsenic trioxide AS203 radical in a water soluble compound is generally the active constituent for the purpose of this invention. The invention, though, is not to 'be understood to be limited only to the use of water soluble arsenic compounds, as relatively insoluble arsenic compounds may be incorporated by the use of a suspension thereof, or for example sodium arsenate maybe used which in a water solution hydrolyzes to form arsenic acid .H AsO Other metalloids of the arsenic family, though generally less toxic, act in a manner similar to arsenic and of course may be utilized if sufiiciently toxic for the desired specific use.

The arsenious acid, as for example in the form of sodium arsenite, is preferably added to the watersuspension of fiber first, and then,

emulsion usually formed by heating and agitating the rosin with an alkali. The amount of rosin emulsion is expressed in per cent of solids in the emulsion or suspension form in which it is added. For the best and uniform results it is desirable and advisable that the arsenious acid and rosin emulsion added to the fiber suspension be fairly well mixed therewith in order that a uniform treatment may be obtained.

In using the term sizing agent above, it is contemplated that any of the water repellent sizing agents which are used or are usable in sizing paper and board fibers may be used, that is,,rosin, resins, asphalts, waxes, paraflines, fatty acids, and the like, which sizing materials are mentioned only as illustrative and not as all-inclusive.

After the rosin emulsion and arsenious acid have been thoroughly mixed through the fluid suspension of fiber there is added approximately 2% of iron salts which insolution will form a hydrated oxide of iron, as for example ferric chloride based on the dry weight of fiber, which solution may comprise a combination of salts such as both ferric chloride and ferric sulphate, in which event this solution should be added in an amount sufficient to form the amount of hydrated oxide of iron necessary for coagulation and precipitation of the arsenic and rosin.

Upon addition of the size precipitant and coagulant to the fiber containing the arsenic and rosin, there is an action which is probably a combination of chemical and physical phenomenon whereby the arsenic and rosin are deposited on the fiber as precipitates or are adhered by absorption, or are probably more orless both deposited on and adhered to the fiber. It may be that when the ferric chloride is added the stock is outside the range of acidity oralkalinity within which the sizing, will be deposited most satisfactorily on the fibers, which range is approximately between the pH of 4.0 and 8.0, in

which case an adjustment may be made with sodium hydroxide or other alkali to bring the pH within the most satisfactory range, which for tl e purpose of the invention, when using ferric chloride and sodium arsenite, is apparently a pH of between 4.5 and 5.5. The action in this method of sizing and providing fungi and insect proofing of the board is apparently due to the fact that the ferric chloride reactsto form ferric hydroxide, a hydrated oxide of' iron, or basic ferric salts under conditions of and within the pH range of the treatment. The ferric hydroxide apparently acts on the rosin emulsion in the same general manner as does alum with the result that apparently a resinate of iron is deposited on the fiber in the place of the alum resinate ordinarily present in the usual sorbing arsenic than is ferric hydroxide which there is a chemical reaction which occurs,v

has been previously made and allowed to stand, and it is for this reason that the iron salt is preferably employed in the form of a soluble ferric salt.

The actionof the freshly formed ferric hydroxide or basic ferric salts formed upon addition of ferric chloride to the water suspension of fiber anoears to consist in simultaneous and separate actions, that is, the freshly formed ferric hydroxide apparently absorbs arsenious acid to form a complex colloid in turn adsorbed by the fiber, or possibly the action may be the other way, that is, the iron salt may be adsorbed by the fiber to in turn absorb the arsenious acid. It appears that at the same time that the physical phenomenon just mentioned takes places that whereby the rosin of the rosin sizing emulsion is coagulated and precipitated on the fibers.

The two actions just described as possible explanations of this process appear to be car- .ried out substantially simultaneously and independently, that is, the addition of sufficient ferric chloride to absorb the arsenic is sufiicient to cause the coagulation and precipitation of the rosin size om the rosin emul- 'sion which has been added, otherwise additional ferric chloride isunnecessary over that used for providing only insect and fungi tional ferric. chloride will impart a brown color to the fiber, the'intensity of which of course depends {upon the amount of ferric chloride. By .varying the. amount of ferric chloride, it is possible to control the shade of color imparted to the'finished fiber products made from the fiber which has beentreated accordance with thisinvention.

.bya

Should the color imparted by the necessary amount of ferric chloride, whlch is ordinarily of necessity for the conservation of arsenic used somewhat in excess of the minimum, give too dark a shade of color to the fiber, a small amount of alum may be used to assist in the coagulation and precipitation of the size whereby a final product of lighter shade may be obtained. The entire precipitation may be brought about by the use of alum aloneor by other appropriate. precipitating agent,but of course in such case the coloring effect of the iron salt will not be had. 4

The general proportions heretofore given, that is, the addition of approximately 1%% arsenic, 1% of size and 22 ferric chloride, will produce aboard, or product, which is water, insect and fungi proofed, but with the proportions given there is some loss of arsenic that has not been absorbed by the ferric hydroxide and thereby afiixed to the fibers. This loss mentioned is dictated by economic reasons in-balancing the amount of ferric chloride used against arsenic loss and of course this will be somewhat increased or decreased depending upon variation of the amounts-of the materials used as dictated b economic consideration for economical pro uction. In order that ,this arsenic loss' just mentioned may be saved, it is of course possible to v operate the process as a closed system or there has been devised a serial process whereby the arsenic which would otherwise go to waste may be advantageously used. The white water or waste water resulting from the formation of products from the fluid suspension of fiber in the manner which is well known, as for instance in the manufacture of fiber insulating-board,is utilized in a similar process wherein it is suflicient to only provide a fun proofness against wood destroying orgamsms without mcluding the property of insect proofness. f

The white water of the first system is used as makeu ilwater for the second system wheresma amount of arsenic is present in the fluid suspensionof the fiber. To this fluid suspension there is added 1% of rosin emulsion and about 1 ;%'ferric chloride, with the result that the ferric chloride coagulates and precipitates the rosin size and at the same time absorbs and attaches the arsenic to the fibers, all in a manner substantially as here 'tofore described, except thatsince there is only relatively a trace of arsenic present,

preferably approximately 0.05 to 0.25 per cent, the products are rendered fungi proof.

only, and do not have .the insect proofness afforded by a larger arsenic content.

Whereasthe use of ferric chloride has been particularly described, it is to be understood that if desired "equivalent results may be had by the use of ferrous sulphate, which in the i I solution forms ferrous hydroxide; which is eventually, in thecourse of the usual drying ride, ferric sulphate, ferrous chloride and ferrous sulphate present.

While inthis specification there have been mentioned in various placescomplex colloid and precipitate, attention is directed to the fact that so far as the invention hereof is concerned, the words colloid and precipitate should be used in substantially an interchangeable sense; that is, the chemistry of the reactions which occur is not in all cases clear and it is very possible-and even probable that certain actions .which are referred to as precipitations actually involve colloid phenomena, whereas certain actions referred to as colloid phenomena probably involve pure precipitation, and further it is quite probable that many of the reactions involved comprise the combination of chemical precipitation and colloid phenomena.

There having been above described the preferred embodiment of the invention,

We claim:

. 1. Fiber which is water, insect and fungi proofed with a complex colloid comprising, in part, iron, arsenic and rosin.

2. Fiber products sized and rendered fungi proof and insect toxic with rosin, arsenic and ferric chloride.

' senic trioxide radical, and a compound of iron having as an element thereof ferric chloride, when in water solution and in the presence of vegetative fiber.

6. A product comprising fibers derived from vegetative sources having incorporated integrally therein a sizing, insecticide and fungicide comprising the precipitate formed in a water solution containing rosin size, arsenious acid and hydrous ferric oxide.

7. The method of water proofing and protecting fiber derived from vegetative substancesfrom attack by insects, fungi, and the like, comprising the incorporation therein of an insoluble colloidal complex including a sizing agent, arsenious acid and hydrous oxide of iron.

8. The method of water proofing and of protecting fiber derived from vegetative sources from attack by insects, fungi, and the like, wherein arsenious acid and a sizing agent as elements of a relatively insoluble colloidal complex are incorporated in the fiber.

9. The method of water proofing and of protecting vegetative substances from attack by insects, fungi, and the like, comprising the addition, to a water suspension thereof, of an emulsion of a sizing agent, arsenious acid, and ferric chloride, the pH of the solution adjusted to between pH 1-0 and pll 8.0 with subsequent removal of the water from the substances.

10. Vegetative fiber to which while in dilute water suspension there has been added about 2% of arsenious acid, 1% of rosin size, and 2 75 of ferric salts comprising principally ferric chloride.

11. Vegetative fiber to which While in dilute water suspension there has been added about 1 to 4: per cent of arsenious acid, 0.5 to 2 per cent of rosin size and 1 to 8 per cent of ferric salts comprising principally ferric chloride.

12. Vegetative fiber to which while in water solution there has been added about 0.05 to 1.0 per cent of arsenious acid, 0.5 to 2 per cent of rosin size and 1 to 8 per cent of ferric salts comprising principally ferric chloride.

13. The method of manufacture of a water and fungi proofed board comprising the formation thereof from a water suspension of vegetative fiber containing arsenious acid, a sizing agent, and hydrated oxide of iron, and wherein the arsenious acid is supplied principally as makeup water of suspension derived from a similar like process of manufacture of fiber board but wherein the initial arsenious acid content was greater.

14. The method of serial manufacture of fiber products from fiber derived from vegetative materials wherein the first product is water, insect and fungi proofed and the s l 1c ceeding product is water and fungi proofed, and wherein the first product is formed from a water suspension of fiber having distributed therethrough a complex colloid formed from principally arsenious acid, a Water proofing sizing agent, and a ferric salt consisting principally f ferric chloride and the succeeding arsenic content of the succeeding prodnct' lower than that of the first product and derived from the white water or waste water of the first step of product formation to the second step as makeup water therefor.

15. Fiber products sized, rendered fungi proof and insect toxic through incorporation therein of a complex chemical colloid resulting from interaction. of a sizing agent, by-

drous-oxide of iron and arsenic.

16. Fiber products sized and rendered fungi proof and insect toxic with rosin, arsenic,

ferric chloride, and alum.

17. A vegetative fiber mass having inc'orporated therein a colloidal complex comprising a sizing agent, ferric hydroxide, arsenious acid, and alum.

18. The method of rendering vegetative fiber products water repellent, insect and fungi proof, wherein the water repellent properties and the insect and fungi proofing are obtained through addition, to a dilute. suspension of fiber in water, of a hydrolyzable salt of a metalloid of the arsenic family, and a water repellent paper size,the metalloid and L- the paper size subsequently thrown down on the fiber by the addition of a salt ofa metallic element the hydroxide of which is gelatinous, the pH of the suspension being p'roperly'adjusted to a value to bring about the desired precipitation of the metalloid and the gelatinous hydrate on the fiber;

19. A vegetative fiber product rendered water repellent and insect and fungi proof by the inclusion therein of a complex colloid resulting from treatment of the fiber, while in dilute suspension, with an iron salt principally consisting of ferric chloride, a water repellent size, and a salt of arsenic which in Water solution hydrolyzes to form oxide ions of arsenic.

20. A vegetative fiber product rendered water repellent and insect and fungi proof by the inclusion therein of a complex colloid resulting from treatment of the fiber, while in dilute suspension, with an iron salt princixpally consisting of ferric sulfate, a water repellent size, and a salt of arsenic which in water solution hydrolyzes to form oxide ions of metalloid of the arsenic family, and a water through addition, to a dilute suspension of fiber in water, of a hydrolyzable salt of a repellent pa er size, the metalloid and the paper size su sequently thrown down on the fiber by the addition of a salt of a metallic element the hydroxide of which is gelatinous, and paper makers alum, the pH of the suspension being properly adjusted to a value to bring about the desiredprecipitation of-the metalloidand the gelatinous hydrate on the .22. The method of rendering vegetative fiber products water re ellent, insect and fungi proof, wherein t e water repellent propert es and the insect proofing are obtained through addition, to a dilute suspension of fiber in water, of a salt of arsenic and a water repellent size, the salt of arsenic and the fiber size subsequenty thrown down on the fiber by the addition of a precipitant, the pH of the suspension being properly adjusted to bring about the desired precipitation of the salt of arsenic and the size on the fiber.

23.' The method of rendering vegetative fiber products water repellent, insect and fungi proof, wherein the water repellent properties and the insect proofing are obtained through addition, to a dilute suspension of fiber in water, of a salt of arsenic and a water repellent size, the salt of arsenic and the fiber size subsequently thrown down on the fiber by the addition of alum, the pH of the suspension being properly adjusted to bring about the desired precipitation of the salt of arsenic and the size on the fiber.

24. A vegetative fiber product rendered water repellent and insect and fungi 'toxic by the inclusion therein ofa chemical complex resulting from treatment of the fiber, while in dilute suspension; with alum, a repellent size, and a salt of arsenic which in water solution hydrolyzes to form oxide ions of arsenic. V

25. A vegetative fiber product rendered water repellent and insect and fungi toxic by the inclusion therein of a chemical complex resulting from treatment of the fiber, while in dilute suspension, with a precipitant,

- a repellent size, and a salt of arsenic which in water solution hydrolyzes to form oxide and fungi, and wherein the repellent prop- Y erties thereof are obtained through treatment of the fiber, in dilute water suspension, with rosin size and sodium arsenate, the size: and the arsenic thrown down on the fiber by -the addition of'alum.

28. The method of rendering vegetative fiber products water repellent, insect and fungi toxic, wherein the water repellent properties and toxicity are obtained through 7 treatment of the fiber, in dilute water su nsion, with rosin size 0.25 to 4% ands um arsenate 0.005 to 0.40% (arsenic content), the

' arsenic and rosin thrown down on the fiber by the addition of to adjust the pH of the suspension to between pH 4.0 and pH 7.5.

29. The method of rendering vegetative fiber products water repellent, insect and fungi toxic, wherein the water repellent properties and toxicity are obtained through treatment of the fiber, in dilute Water suspension, with wax size 0.5 to 10% and sodium arsenate 0.005 to 0.40% (arsenic content), the arsenic and wax thrown down on the fiber by the addition of alum to adjust the pH of the suspension to between pH.4.0 and pH 7.5.

30. A felted fibrous product composed of vegetative fiber and having distributed throughout the body thereof the reaction product of rosin size, sodium arsenate and a coagulant and precipitant thereof.

In testimony whereof, we have signed our names to this specification as of the 23rd day of December, A. D. 1930.

TREADWAY B. MUNROE. ELBERT C.- LATHROP. 

